/// <include file='doc\RichTextBox.uex' path='docs/doc[@for="RichTextBox.CharRangeToString"]/*' />
/// <devdoc>
/// Converts a CHARRANGE to a string. Note: The behavior of this is dependent on the current window
/// class name being used. We have to create a CharBuffer of the type of RichTextBox DLL we're using,
/// not based on the SystemCharWidth.
/// </devdoc>
/// <internalonly/>
private string CharRangeToString(NativeMethods.CHARRANGE c) {
NativeMethods.TEXTRANGE txrg = new NativeMethods.TEXTRANGE();
txrg.chrg = c;
Debug.Assert((c.cpMax-c.cpMin)>0, "CHARRANGE was null or negative - can't do it!");
//Windows bug: 64-bit windows returns a bad range for us. VSWhidbey 504502.
//Putting in a hack to avoid an unhandled exception.
if (c.cpMax > Text.Length || c.cpMax-c.cpMin <= 0) {
return string.Empty;
}
int characters = (c.cpMax-c.cpMin) + 1; // +1 for null termination
UnsafeNativeMethods.CharBuffer charBuffer = UnsafeNativeMethods.CharBuffer.CreateBuffer(characters);
IntPtr unmanagedBuffer = charBuffer.AllocCoTaskMem();
if (unmanagedBuffer == IntPtr.Zero)
throw new OutOfMemoryException(SR.GetString(SR.OutOfMemory));
txrg.lpstrText = unmanagedBuffer;
int len = (int)UnsafeNativeMethods.SendMessage(new HandleRef(this, Handle), RichTextBoxConstants.EM_GETTEXTRANGE, 0, txrg);
Debug.Assert(len != 0, "CHARRANGE from RichTextBox was bad! - impossible?");
charBuffer.PutCoTaskMem(unmanagedBuffer);
if (txrg.lpstrText != IntPtr.Zero)
Marshal.FreeCoTaskMem(unmanagedBuffer);
string result = charBuffer.GetString();
return result;
}
/// <include file='doc\RichTextBox.uex' path='docs/doc[@for="RichTextBox.Find6"]/*' />
/// <devdoc>
/// Searches the text in a RichTextBox control for the given characters.
/// </devdoc>
public int Find(char[] characterSet, int start, int end) {
// Code used to support ability to search backwards and negate character sets.
// The API no longer supports this, but in case we change our mind, I'm leaving
// the ability in here.
bool forward = true;
bool negate = false;
int textLength = TextLength;
if (characterSet == null)
throw new ArgumentNullException("characterSet");
if (start < 0 || start > textLength)
throw new ArgumentOutOfRangeException("start", SR.GetString(SR.InvalidBoundArgument, "start", start, 0, textLength));
if (end < start && end != -1)
throw new ArgumentOutOfRangeException("end", SR.GetString(SR.InvalidLowBoundArgumentEx, "end", end, "start"));
// Don't do anything if we get nothing to look for
if (characterSet.Length == 0)
return -1;
int textLen = SafeNativeMethods.GetWindowTextLength(new HandleRef(this, Handle));
if (start == end) {
start = 0;
end = textLen;
}
if (end == -1) {
end = textLen;
}
NativeMethods.CHARRANGE chrg = new NativeMethods.CHARRANGE(); // The range of characters we have searched
chrg.cpMax = chrg.cpMin = start;
// Use the TEXTRANGE to move our text buffer forward
// or backwards within the main text
NativeMethods.TEXTRANGE txrg = new NativeMethods.TEXTRANGE(); // Characters we have slurped into memory in order to search
txrg.chrg = new NativeMethods.CHARRANGE();
txrg.chrg.cpMin = chrg.cpMin;
txrg.chrg.cpMax = chrg.cpMax;
UnsafeNativeMethods.CharBuffer charBuffer;
charBuffer = UnsafeNativeMethods.CharBuffer.CreateBuffer(CHAR_BUFFER_LEN + 1);
txrg.lpstrText = charBuffer.AllocCoTaskMem();
if (txrg.lpstrText == IntPtr.Zero)
throw new OutOfMemoryException();
try {
bool done = false;
// We want to loop as long as it takes. This loop will grab a
// chunk of text out from the control as directed by txrg.chrg;
while (!done) {
if (forward) {
// Move forward by starting at the end of the
// previous text window and extending by the
// size of our buffer
txrg.chrg.cpMin = chrg.cpMax;
txrg.chrg.cpMax += CHAR_BUFFER_LEN;
}
else {
// Move backwards by anchoring at the start
// of the previous buffer window, and backing
// up by the desired size of our buffer
txrg.chrg.cpMax = chrg.cpMin;
txrg.chrg.cpMin -= CHAR_BUFFER_LEN;
// We need to keep our request within the
// lower bound of zero
if (txrg.chrg.cpMin < 0)
txrg.chrg.cpMin = 0;
}
if (end != -1)
txrg.chrg.cpMax = Math.Min(txrg.chrg.cpMax, end);
// go get the text in this range, if we didn't get any text then punt
int len;
len = (int)UnsafeNativeMethods.SendMessage(new HandleRef(this, Handle), RichTextBoxConstants.EM_GETTEXTRANGE, 0, txrg);
if (len == 0) {
chrg.cpMax = chrg.cpMin = -1; // Hit end of control without finding what we wanted
break;
}
// get the data from RichTextBoxConstants into a string for us to use.
charBuffer.PutCoTaskMem(txrg.lpstrText);
string str = charBuffer.GetString();
// Loop through our text
if (forward) {
// Start at the begining of the buffer
for (int x = 0; x < len; x++) {
// Is it in char set?
bool found = GetCharInCharSet(str[x], characterSet, negate);
if (found) {
done = true;
break;
}
// Advance the buffer
chrg.cpMax++;
}
}
else { // Span reverse.
int x = len;
while (x-- != 0) {
// Is it in char set?
bool found = GetCharInCharSet(str[x], characterSet, negate);
if (found) {
done = true;
break;
}
// Bring the selection back while keeping it anchored
chrg.cpMin--;
}
}
}
}
finally {
// release the resources we got for our GETTEXTRANGE operation.
if (txrg.lpstrText != IntPtr.Zero) Marshal.FreeCoTaskMem(txrg.lpstrText);
}
int index = (forward) ? chrg.cpMax : chrg.cpMin;
return index;
}
